This invention relates to the art of pneumatic valves and more particularly to means implementing the use of pneumatic valves to control air flow for textile machinery blowdown and the remote control of a pneumatic valve of the type in which a flexible annulus is arranged within a conduit with a fluid containing space between the side walls of the conduit and the annulus such that upon a build-up of fluid pressure in this space, the flexible annulus will become constricted to prevent flow through the conduit. A variety of controls have been evolved for controlling and regulating the flow of valve actuating fluid to the space between the annulus and the relative rigid conduit sidewall of these pneumatic valves. However, where the control valves are remotely located as they usually are in any industrial situation, such for example, as in a textile mill where a variety of pneumatic cleaning and waste collection systems may be employed, a central control panel is generally installed to effect control of the pneumatic system. Vented solenoid actuated valves at the central control station are generally employed to control the flow of control fluid (generally air) to the remotely located pneumatic valve to effect constriction of the flexible annulus in the pneumatic valve.
When it is desired to open the pneumatic valve, the centrally positioned vented control valve is actuated to cut off the flow of the annulus constricting fluid permitting the annulus to distend to its normal position permitting flow to the duct work in connection with which the pneumatic valve is employed, with the control fluid in the system between the control valve and the pneumatic valve vented to ambience through the control valve.
Depending on the distance of the control valve from the pneumatic valve, it is found that the release of the constricting air which must flow back to the control valve often occurs significantly later than the time that the solenoid valve was initially activated to cut off the flow of pneumatic valve control air, thus producing an undesirable time delay between initiation and completion of the control action opening the pneumatic valve.
Where an attempt is made to avoid the time delay between control valve actuation and pneumatic valve response by arranging the control valve in proximity to the pneumatic valve and employing a remote switch at a central control panel to actuate the control valve, the wiring between the central control panel and the control switch increases installation, operation and maintenance costs.